Supplementation with a Natural Source of Amino Acids, Sil-Q1 (Silk Peptide), Enhances Natural Killer Cell Activity: A Redesigned Clinical Trial with a Reduced Supplementation Dose and Minimized Seasonal Effects in a Larger Population.

Jung Min Cho,Jeong-Yong Lee,Jong Ho Lee,Dokyeong Yoo,Mi-Sun Oh,Hye Jin Yoo,Ki-Chan Ha,Hyang-Im Baek,Seung-Min Lee

doi:10.3390/nu13092930

Abstract

The aim of this study was to re-validate the changes in natural killer (NK) cell cytotoxicity and cytokines related to T cells after Sil-Q1 (SQ; silk peptide) supplementation in a larger pool of Korean adults with minimized daily dose of SQ and controlling seasonal influence compared to the previous study. A total of 130 subjects were randomly assigned (1:1) to consume either 7.5 g of SQ or placebo for 8 weeks. NK cell cytotoxicity and cytokines were measured at T0 (baseline) and T8 (follow-up). Comparing the NK cell cytotoxicity values at T0 and T8 within each group, the cytotoxicity at all effector cell (E) to target cell (T) ratios of 10:1, 5:1, 2.5:1, and 1.25:1 was significantly increased in the SQ group at T8. Additionally, significant differences in the changed value (Δ, subtract baseline values from follow-up values) comparison between the groups at E:T = 10:1, 5:1, and 2.5:1 were found. As a secondary endpoint, the interleukin (IL)-12 level in the SQ group was significantly increased for 8 weeks, and Δ IL-12 in the SQ group was greater than in the placebo group. In conclusion, the present study showed considerable practical implications of SQ supplementation. Thus, SQ is an effective and safe functional food supplement for enhancing immune function.

Highlights

Populations are vulnerable to alterations and disorders of immune function with age [1,2]
Verifying the results of demographic and anthropometric data, it was judged that the selection and allocation of subjects were appropriately made, and there was no significant difference between the two groups in any baseline values
The novel findings of this confirmatory RCT indicated that daily supplementation with 7.5 g of Sil-Q1 enhanced natural killer (NK) cell cytotoxicity and IL-12 levels

Summary

Introduction

Populations are vulnerable to alterations and disorders of immune function with age [1,2]. Some studies have reported that dietary interventions can reduce the risk of deterioration of the immune system [3,4,5]. Functional food plays a crucial role in physical well-being and advancing physiological functions as a concept of preventive medicine [6,7,8]. Silk is a fiber made by silkworms and has been used only as a high-quality material for clothing for a long time. The amino acids that compose silk activate cells and tissues, causing the normal growth and division of cells. Known by the brand name ‘Sil-Q1 (SQ)’, is an amino acid complex produced by acid hydrolysis of the silk cocoon

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